[单选题] of the following is a correct statement? A tis best to have 10 to 12 candidates of all levels at qualificators per job capering in the candidates pool B tis best to have 3 to 5 (or more) candidates per job opening in the candidate pool C Lis best to waturt a job absoutely needs to be filed to begn the employmert process to ensure that candidates wel sal be avarlsble when job olfers are made D Candidates should not be ranked according to their performance in the interview